The Dual Paradigm of Mining Waste: “From Ecotoxicological Sources to Potential Polymetallic Resources”—An Example from Iberian Pyrite Belt (Portugal)

Abstract

The main goal of this study was to identify potential chemical elements present in three types of polymetallic mine waste, stored in the old mine site of São Domingos, located in the Iberian Pyrite Belt, Alentejo, Southern Region of Portugal. This study involves the characterization of potential resources in those mine residues, bearing in mind that its reprocessing can facilitate the environmental remediation and rehabilitation activities which are underway at the site. X-ray Fluorescence (XRF) and micro (μ)-XRF 2D mapping surveys were performed. Univariate and multivariate data analysis reveal that differences in compositions are mainly related with element concentration per type of waste. Image processing and clustering analysis allowed the recognition of distinct elemental spatial distribution patterns. Some of these residues, although classified as archeological-industrial heritage materials may present toxicity to the ecological environment and to human health. This fact enhances, therefore, geoethical doubts regarding its remining and exploitability. In this context, a multi-criteria decision analysis considering two geoethical alternatives was performed.